Broach with adjustable broaching members



Now 27, 1.928. I

, W. DE VOE ET AL.

BROAOH WITH ADJUSTABLE BROACHING MEMBERS Filed May 23, 1927 72 4? z 55-:MHZ am: H

V62 (Ewe: J: 115/0 Fatente d Nov. 2?, i928.

s ren STATES I mew PATENT orrics.

WILLIAM DE VOE, OE WORCESTER, MASSACHIJ'SETTS, AND JAMES J. WABD, OF DE-TROIT, MICHIGAN, ASSIGNOBS TO DETROIT BROAGH CORPORATION, OF DETROIT,MICHIGAN, A CORPORATION OF MICHIGAN.

BROAGH WITH ADJUSTABLE BBOACHING MEMBERS.

Application filed May 28, 1927. Serial No. 193,467.

This invention relates to a broach duch as is used for accuratelyfinishing holes to a desired form and size. Such tools are widely usedto finish center holes in cams, gears,

a collars or sleeves, for providin spiral keyses. In the general use ofa broach of this na ture the cutting elements partake of a substantiallylongitudinal movement, although ways, and for many other -si ar purpo doin the useof cutting a spiral key-way there will, ofcourse, be a slightrotary movement accompanying the longitudinal movement, that is to say,the general cutting action of the broach is substantially longitudinal,but

115 contains a small proportion of rotational movement. I It is thegeneral object of our inventlon to provide a breach with a plurality ofseparate broaching members which may beeasily adjusted radially. Withthis construction, a

worn broach may be restored to size by setting the broaching membersoutward and then grinding their eripl ieral surfacesagain to size,instead of y face grinding the cutting 2 faces of the broach, as isnecessary with the usual one-piece breach.

A further object of our, invention is to provide an improvedconstruction for securing the breaching members to the supportingradially, as and-when desired.

Our invention further'relates to certain arrangements and combinationsof parts which will be hereinafter described and more particularlypointed out in the appended claims. Y

A preferred form of the invention and cer-' tain modifications thereofare shown in the drawings in which Fig. 1 is a side elevationof one formof our improved breach;

Fig. 2 is a side elevation of a portion of the supporting shaft;

igs. 3 and-4 are transverse sectional elevvatipns taken along the lines3'-3 and 4'-4: .in i 1; v p

Fig? 5. is a side view of one of theb'roaching members;

Fig. 6 is an end .view thereof;

Figs. 7, 8 and 9 are side views of breaching members for cuttingdifferent shaped bodysor shaft of the broach, and for simultaneouslyadjusting said members axially and overlap at their ends, as shown inFig. 10 is a detail sectional side elevation, illustrating amodification; and

-Fig. 11 is a partial sectional end e1eva tion, showing a furthermodification.

Referring to the drawings, our improved broach comprises a supportingshaft 20 having an end portion 21 adapted to fit into a breach holder orchuck and having a transverse opening 22 through which a key or stud maybe inserted to hold the breach in the holder. Both end portions of theshaft 20 are preferably threaded to receive adjusting nuts 24 and locknuts 25. u The middle portion of the supporting shaft 20 is providedwith a plurality'of flat bearing surfaces 26, spaced about the axis ofthe breach as indicated in Figs. 3 and 4, and each provided with anundercut or dovetailed guideway or recess 27. The bearingsurfaces 26 areinclined with. respect to the axis of the broach, the angle shown in thedrawings being substantially 10. This angle is illustrative only and maybe increased or decreased in accordance with the work to be performed.

The surfaces 26 are preferably arranged in groups, each of which, asshown in Figs. U 3 and 4, comprises three surfaces 26 symmetricallyarranged about the axis of the breach. The bearing surfaces of one grouppreferably overlap the bearin surfaces of the next group, and arepositioned axially and angularly substantially midway between thebearing surfaces of the next successiv group; i

A broaching member 30 is mounted on each bearingsurface 26 and isprovided with an over hanging or dove-tailed projection 31, fitting theguideway or recess 27. The broach as illustrated in Figs. 1 to 6 isdepreferably forms a segment of a cone with the extreme edge portion 33substantially cylindrical.

' The side faces 34 and 35 of the breaching members are disposed at suchan angle to their inner faces 36 that they will be perpendicular to theaxis-of the breach. when inworking position. The breaching members 30are of such circumferential width that the breach members of successivelgroups 105 and 4, thus broaching the complete inner surface of the holeto be finished.

In the operation of our improved broach,-

I the broaching members 30 are mounted in thedove-tailed recesses 27,and spacing collars are interposed between successive groups ofbroaching members. Collars or sleeves 41 of greater length may be usedat the ends of the broach to fill up the space not occupied by thebroaching members. The collars 41 are engaged by the adjusting nuts 24,which are used to clamp the collars and broaching members firmlytogether, after which the broaching members may be ground on their outerperipheral surfaces to the desired size of the finished hole.

After a large number of broaching operations have been performed, sothat the sharp edges of the broaching members have become du l or worn,the broaching members are adjusted toward the right, as viewed in Fig.1, by loosening'the right hand nut 24 and i advancing the left hand nut24. This will produce axialmovement of all of the broaching members,with a corresponding outward or radial movement of said members. Whenthe broaching members have thus been slight- 1y expanded, the broachingmembers may be again ground on their peripheral faces to restore thesize and sharp cutting edges of the broachin members. a

It will e noted that the only grinding operation is plain cylindricalgrinding and that no face grindin is necessary, as was the case in theold style roaches. This operation of expanding and regrinding will berepeated as often as is necessary, until the broaching members have beenmoved to the extreme outer ends of the bearing surfaces 26, whenthey maybe removed and replaced by new members at relatively small expense. Oneor more pilot collars 42 may be used at the entering end-of the broachif desired.

While we have indicated the broaching members, as arranged in alternategroups of three members each, it' will be understood that any otherdesired number of broaching members may be used, and that they may be.variously grouped. It is evident also that our broach may be modifiedby forming the dove-tailed projections 45 (Fig. 11) on the bearingsurfaces 46 and by forming the dove tailed recesses 47 in the broachingmembers 48. f

While we. have shown and. described a broach for finishing circularholes, we have indicated in Figs. 7, 8 and 9 that the broach members 50may be fvariously shaped, to

broach hexagonal or octagonal holes, or holes y membersslmultaneouslyaxially on said surhaving any other 'desired crosssection. In a broach of the type designed for cutting keyways, it willbe appreciated that the crosssection of the broach member will besuitably shaped. I

While the general cutting movement of the broach is lon 'tudinal withrespect to the work-piece it Is evident that a small proportion ofrotational movement may be intro duced if desired or necessary. 1

In Fig. 10, we have illustrated a further modification in which thebroaching members have their side faces 61 and 62 formed perpendicularto the bearing surfaces 63, instead of perpendicular to the axis of thebroach. The spacing collars 64 used with such broaching members Will beprovided with bevelled ends corresponding to the inclination of thesurfaces 61 and 62 with respect to the axis of the broach. This form ofbroaching member provides a natural rake for the cutting face, withoutthe necessity of under cutting the side faces of the broaching me-mbers,and is very desirable in many cases. K

Having described our invention and the 4 method of using the same, theadvantages thereof will be readily apparent. The broaching members maybe expanded outwardly and reg'round to size a great number stantiallyreducing the users investment.

compared'with that of maintaining a stock of the old-style, solidbroaches.

Having thus described our invention and the advantages thereof, we donot wish to be limited to t-he details herein di closed, otherwise thanas set forth in the cla1 s, but what we do claim is:

1. An adjustable broach for finishing internal work by relative movementlongitudinall thereof, comprising a supporting shaft having a pluralityof bearing surfaces spaced apart, both axially and circumferentially,and inclined outwardly with respect'to the broach axis, and a separatebroaching member seated on each bearing surface and firmly retained inposition thereon, said broaching members being adjustable axially ofsaid broach to vary the radial position of their outercircumferentialsurfaces.

.2. An adjustable broach for finishing internal work by relativemovement longitudinally thereof, comprising a supporting shaft having aplurality of bearing surfaces spaced apart, both axially andcircumferentially, and inclined outwardly with respect to the broachaxis, a plurality of broaching members slidably mounted on said bearingsuraces, and means to move said broaching thereof, comprising asupporting shaft having a plurality of bearing surfaces arrangedsubstantially on the periphery thereof and spaced apart, both axiallyand circumferentially, and? inclined outwardly with respect 5 to thebreach axis, a plurality of breaching membersslidably mounted on saidbearing surfaces, said breaching members bein located in successiveparallel planes along t e axis of said breach, and means to secure saidbreaching members on said bearing surfaces.

4:. An adjustable breach for finishing internal work-by relativemovement longitudinally thereof, comprising a supporting shaft having aplurality of bearing surfaces arranged substantially on the peripherythereof and spaced apart, both axially and circumferentially, andinclined outwardly with respect to the breach axis, a plurality ofbreaching members slidably mounted on said bearin surfaces, saidbreathing members being located in successive parallel planes along theaxis of said breach and the breaching members in one plane having theirends circumferentially overlapping the ends of the 'b'ri'oachingjmembers in each next adjacent p ane.

5,. An adjustable breach for finishing internal work by relativemovement longitudinally thereof, comprising a supporting shaft having aplurality efbearing surfaces spaced apart, both axially andcircumferentially, and inclined outwardly with respect to the breachaxis, a plurality of'broaching members slidably mounted on said bearingsurfaces and arranged in circumferential groups, spacing collarsseparating said groups of breaching members, and means to move all ofsaid collars and members axially to adjust tube radial positions of saidbreaching memers, 4

6. An adjustable breach forfinishing internal work by relative movementlongitudinally thereof, comprising a supporting shaft having a pluralityof bearing surfaces are ranged substantially on the periphery thereofand spaced apart, both axially and circumferentially, and inclinedoutwardly with respect to the breach axis, a plurality of breachingmembers slidably mounted on said bearso ing surfaces, spacing collarsseparating said breaching members, and lock nuts threaded on saidsupporting shaft and effective to move said collars and said breachingmembers axially on said shaft to adjust the radial position of saidbreaching members,

7. An adjustable breach for finishing internal. work by relativemovement longitudinally thereof, comprising a supporting shaft having aplurality of bearing surfaces arranged substantially on the peripherythereof and spaced apart, both axially and circumferentially, andinclined outwardly with respect to the breach axis, a plurality, ofbreaching members slidably mounted on said bearing surfaces, each of oneset of parts having an undercut axially-extended guiding recess and eachof the other set of parts having a corresponding overhanging pro ectionfitting therein.

8. An adjustable breach for finishing internal work by relative movementlongitudinallythereof, comprising a supporting shaft having a pluralityof bearing surfaces arranged substantially on the peripherv thereof andspaced apart, both axially and circumferentially, and inclined outwardlywith respect to the breach axis, a plurality of breaching membersslidably mounted on said bearing surfaces, said shaft having undercutaxiallyextended guiding recesses formed in said bearing surfaces, andsaid breaching members having dove-tailed projections fitting saidrecesses.

9. An adjustable breach for finishing internal work by relative movementlongitudinally thereof, comprising a supporting shaft having a pluralityof bearing surfaces, arranged substantially on the periphery thereof andeach inclined outwardly from the axis of the breach, said surfaces beingarranged ee in axial rows angularly spaced about said shaft, andhaving-each bearing surface ineach row displacedaxiallywith respect tothe bearing surfaces in the adjacent rows, and

breaching members slidably mounted on said bearing surfaces.

10. An adjustable breach for finishing internal work by relativemovement longitudinally thereof, comprising a supporting shaft having aplurality of bearing surfaces, arranged substantially en. the peripherythereof and each equally inclined outwardly from the axis of the breach,said surfaces being arranged in parallel axial rows equally spacedangularly about said shaft, and having each bearing surface in each rowdisplaced axially with respect to the bearing surfaces in J the adjacentrows by substantially half the length of a bearing surface, andbreaching members slidably mounted'en said bearing surfac s. v

11. n adjustable breach for finishing internal work by relative movementlongitudinally thereof, comprising a supporting shaft having 'aplurality of bearing surfaces arranged substantially en the peripherythereof and each equally inclined outwardly from the axis of the breach,said surfaces being arranged in parallel axial rows angularly spaced"about said shaft, and having each bearing surface in each row displacedaxially with respect to the bearing surfaces in the adjacent rows,breaching members slidably mounted on said bearing surfaces, and arranged in circumferential groups, and means to secure the breachingmembers in each group to said supporting shaft with their cutting edgesin a single plane.

12. An adjustable breach for finishing internal work by relativemovement longitudi nall thereof, comprising a supporting shaft having aplurality of bearing surfaces, each equally inclined outwardly from theaxis of the broach, said surfaces being arranged in parallel axial rowsequally spaced angularly about said shaft, certain of said bearingsurfaces bein displaced axially with respect to the other ear1ngsurfaces, broaching members slidably mounted on said bearing surfaces,certain of said broaching members be- .ing displaced axially withrespect to the other broaching members, means to prevent outwarddisplacement of said broaching members, and means to move said memberssimultaneously axially along said broach, thereby also moving saidmembers radially outward.

13. An adjustable broach for finishing internal work by relativemovement longitudinally thereof, comprising a shaft, having a pluralityof bearing surfaces arranged substantially at the periphery thereof andspaced apart, both axially and. circumferentially, a plurality ofbroaching members each slidably mounted on one of said surfaces, saidbroaching members being located in successive planes along the axis ofthe breach, the members in one plane having their ends circumferentiallyoverlapping the ends of the broaching members in each next adjacentplane.

14. An adjustable broach for finishing internal work by relativemovement longitudinally thereof, comprisin a shaft, having a pluralityof bearin sur aces arranged sub.- stantially at the periphery thereofand spaced apart, both axially and circumferentially, a plurality ofbroaching members each slldably mounted on one of said surfaces, saidbroaching members being located in successive planes along the axis ofthe broach, the members in one plane having their ends axiallyoverlapping the ends of the broaching members in each next adjacentplane.

15. An adjustable broach for finishing internal work by relativemovement longitudinally thereof, comprising a shaft, having a pluralityof bearing surfaces arranged substantially at the periphery thereof andspaced apart, both axially and circumferentially, a plurality ofbroaching members each slidably mounted on one of said surfaces, saidbroaching members being located in successive planes along the axis ofthe broach, the members in one plane having their ends circumferentiallyand axially overlapping the ends of the broaching members in each nextadjacent plane.

In testimony whereof we have hereunto aflixed our signatures.

WILLIAM DE VOE.

JAMES J. WARD.

